Plasmid-mediated colistin resistance from fresh meat and slaughtered animals in the Czech Republic: nation-wide surveillance 2020-2021.

The aim of this study was to determine the occurrence of plasmid-mediated colistin resistance in domestic and imported meat and slaughter animals in the Czech Republic during 2020-2021 by using selective cultivation and direct PCR testing. A total of 111 colistin-resistant isolates with gene were obtained from 65 (9.9%, = 659) samples and subjected to whole-genome sequencing. Isolates with were frequently found in fresh meat from domestic production (14.2%) as well as from import (28.8%). The -positive isolates predominantly originated from meat samples (16.6%), mainly poultry (27.1%), and only minor part of the isolates came from the cecum (1.7%). In contrast to selective cultivation, 205 (31.1%) samples of whole-community DNA were positive for at least one variant, and other genes besides were detected. Analysis of whole-genome data of sequenced isolates revealed diverse sequence types (STs) including pathogenic lineages and dominance of ST1011 (15.6%) and ST162 (12.8%). Most isolates showed multidrug-resistant profile, and 9% of isolates produced clinically important beta-lactamases. The gene was predominantly located on one of three conjugative plasmids of IncX4 (83.5%), IncI2 (7.3%), and IncHI2 (7.3%) groups. Seventy-two percent isolates of several STs carried ColV plasmids. The study revealed high prevalence of genes in fresh meat of slaughter animals. Our results confirmed previous assumptions that the livestock, especially poultry production, is an important source of colistin-resistant with the potential of transfer to humans via the food chain. IMPORTANCE We present the first data on nation-wide surveillance of plasmid-mediated colistin resistance in the Czech Republic. High occurrence of plasmid-mediated colistin resistance was found in meat samples, especially in poultry from both domestic production and import, while the presence of genes was lower in the gut of slaughter animals. In contrast to culture-based approach, testing of whole-community DNA showed higher prevalence of and presence of various variants. Our results support the importance of combining cultivation methods with direct culture-independent techniques and highlight the need for harmonized surveillance of plasmid-mediated colistin resistance. Our study confirmed the importance of livestock as a major reservoir of plasmid-mediated colistin resistance and pointed out the risks of poultry meat for the transmission of genes toward humans. We identified several -associated prevalent STs, especially ST1011, which should be monitored further as they represent zoonotic bacteria circulating between different environments.